Etude de la combustion de gaz de synthèse issus d'un processus de ...

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Chapter 3 mechanical way, by safety) on the way of the carriage in order to stop it, which passes from 0 to 40 km/h and then from 40 km/h to 0. Everything will take 60 ms, which explains the 5 meters length of the machine. Diagnostic systems of RCM tel-00623090, version 1 - 13 Sep 2011 The RCM is equipped with various means of measurement: a laser sensor to measure displacement, inductive sensors positioned along the axis of the piston to start the optical instrumentation and to generate the spark, a sensor to measure the dynamic pressure in the combustion chamber, as well as a thermocouple used during special tests where the chamber is heated, and controlled in temperature. The chamber is equipped with valves intended for the draining and filling of gas mixtures, as well as a secondary cylinder to create controlled aerodynamic effects representative of those found in engines (swirl movement, tumble or homogeneous turbulence). Acquisition and control The RCM control is managed by a PC. The measuring signs (pressure, piston position, wall temperature, heat flux, etc.) are registered simultaneously by a data acquisition (National Instrument 6259) and integrated in the interface. Also some RCM controlling parameters (brakes pressure, hydraulic pressure, piston position, contact cam/lever, etc.) are taking into account for security reasons. The interface also controls the signals of the lasers and camera. Pressure measurement Pressure is measured by a piezoelectric sensor Kistler 601A coupled with an amplifier Kistler 5011B10. This system allows the dynamic measuring of pressure during compression, combustion and expansion. The theoretical precision is about ±1 bar before a significant heat release occurs and ±1.5 bar during and after the ignition. These values include sensor non-linearity error (±0.75 bar) and amplification error. Coupled with an amplifier this measuring system allows registering frequencies higher than 100 kHz in agreement with the used samples. 3.2. Combustion diagnostics Combustion diagnostics used in this work are pressure measurements used for the determination of the flammability limits and burning velocity at constant volume, 67
Experimental set ups and diagnostics schlieren visualizations used for the determination of the burning velocity at constant pressure. Each one is described in the next sub-sections. 3.2.1 Flammability limits The flammability limit is a most widely used index for representing the flammability characteristics of gases. In accordance with generally accepted usage, the flammability limits are known as those regions of fuel–air ratio within which flame propagation can be possible and beyond which flame cannot propagate. And there are two distinct separate flammability limits for the fuel–air mixture, namely, the leanest fuel-limit up to which the flame can propagate is termed as lower flammability limit (LFL), and the richest limit is called as upper flammability limit (UFL). tel-00623090, version 1 - 13 Sep 2011 There are several criteria to determine the flammability limits. A successful attempt can be determined by one or a combination of the following criteria: (1) inspection of the visualization of the flame kernel produced by the spark, namely visual criterion, and (2) measurements of pressure or temperature histories in the vessel and appropriate pressure or temperature rise criteria can be used to designate flammability rather than the purely visual observation of flame development. As we know, a successful ignition would induce a rapid pressure increase and temperature rise within a short time, as well as produce a propagating flame front that could be readily observed. Previous gas flammability limit data were obtained mainly in flammability tubes, in those tests, a gas mixture in a vertical tube was ignited and flame propagation was inspected by a visual criterion. The wall quenching has a significant effect on the flammability measurement in flammability tube. The larger size of combustion chamber can minimize wall effects and can allow for the potential use of stronger igniters to ensure the absence of ignition limitations, so most of the flammability measurements are conducted in closed chambers recently (Liekhus et al., 2000). For safety reasons, to prevent accidental explosions during chemical processes and to classify gas and gas mixtures for storage and transport, there are standards for the determination of the explosion limit in atmospheric conditions that can be found in Schroder and Molnarne, (2005). In general, the explosion limits are affected by the apparatus and material parameters. The most important are: - Flammable mixture composition, type and amount of inert gas, fuel and oxidizer; - Initial pressure and initial temperature; 68
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THÈSE Pour l’obtention du Grade
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Acknowledgements Acknowledgements T
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Résumé __________________________
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Nomenclature Nomenclature Roman tel
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Nomenclature Subscripts tel-0062309
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Contents tel-00623090, version 1 -
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Contents 6.4. SYNGAS FUELLED-ENGINE
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Introduction CHAPTER 1 INTRODUCTION
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Introduction proves to have higher
Page 19 and 20: Introduction Chapter 3 - Experiment
Page 21 and 22: Bibliographic revision CHAPTER 2 BI
Page 23 and 24: Bibliographic revision point today
Page 25 and 26: Bibliographic revision - Boudouard
Page 27 and 28: Bibliographic revision Table 2.1 -
Page 29 and 30: Bibliographic revision Biomass Dryi
Page 31 and 32: Bibliographic revision Circulating
Page 33 and 34: Bibliographic revision or eliminate
Page 35 and 36: Bibliographic revision established
Page 37 and 38: Bibliographic revision Hydrogen Hyd
Page 39 and 40: Bibliographic revision of low moist
Page 41 and 42: Bibliographic revision scrubbing an
Page 43 and 44: Bibliographic revision suggests tha
Page 45 and 46: Bibliographic revision 1 d( δ A) 1
Page 47 and 48: Bibliographic revision Since n is
Page 49 and 50: Bibliographic revision 2 ( rsr ) 2
Page 51 and 52: Bibliographic revision This evoluti
Page 53 and 54: Bibliographic revision The burning
Page 55 and 56: Bibliographic revision δVG = − a
Page 57 and 58: Bibliographic revision 2 1 − −
Page 59 and 60: Bibliographic revision where the su
Page 61 and 62: Bibliographic revision the stretche
Page 63 and 64: Bibliographic revision burning velo
Page 65 and 66: Experimental set ups and diagnostic
Page 69: Experimental set ups and diagnostic
Page 89 and 90: Chapter 4 CHAPTER 4 EXPERIMENTAL AN
Page 91 and 92: Chapter 4 4.1 Laminar burning veloc
Page 93 and 94: Chapter 4 4.1.1.1 Flame morphology
Page 95 and 96: Chapter 4 P i = 1.0 bar, Ti = 293 K
Page 97 and 98: Chapter 4 Figure 4.5 shows schliere
Page 99 and 100: Chapter 4 P i = 2.0 bar, T i = 293
Page 101 and 102: Chapter 4 Sn (m/s) 3.0 2.5 2.0 1.5
Page 103 and 104: Chapter 4 5 ms 10 ms 15 ms 20 ms 25
Page 105 and 106: Chapter 4 behaviour of the curves r
Page 107 and 108: Chapter 4 1.50 Sn (m/s) 1.25 1.00 0
Page 109 and 110: Chapter 4 0.5 0.4 φ =1.0 Su (m/s)
Page 111 and 112: Chapter 4 variation of the normaliz
Page 113 and 114: Chapter 4 4.1.1.6 Comparison with o
Page 115 and 116: Chapter 4 The values of laminar bur
Page 117 and 118: Chapter 4 Pressure (bar) 7 6 5 4 3
Page 119 and 120: Chapter 4 0.5 0.4 φ=1.2 Su (m/s) 0
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Chapter 4 0.3 φ=0.8 Su (m/s) 0.2 0
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Chapter 4 a minimum pressure to exp
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Chapter 4 Notice the similar behavi
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Chapter 4 A very good agreement bet
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Chapter 4 ( ) Q = h T − T (4.21)
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Chapter 4 tel-00623090, version 1 -
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Chapter 4 are tested and discussed.
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Chapter 4 7 500 Pressure (bar) 6 5
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Chapter 4 Pressure (bar) 7 6 5 4 3
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Chapter 4 4.2.3.4 Quenching distanc
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Chapter 4 10000 Quenching distance
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Chapter 5 CHAPTER 5 EXPERIMENTAL ST
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Chapter 5 30 10 25 8 Pressure (bar)
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Chapter 5 30 Piston position (mm) 2
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Chapter 5 5.1.1.4 In-cylinder press
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Chapter 5 estimation of various par
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Chapter 5 TDC 1.25 ms 2.5 ms 3.75 m
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Chapter 5 Piston position (mm) 500
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Chapter 5 From figure 5.15 is possi
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Chapter 5 From figure 5.16 is obser
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Chapter 5 80 Pressure (bar) 70 60 5
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Chapter 5 80 10 Pmax (bar) 70 60 50
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Chapter 5 -5.0 ms -3.75 ms -2.5 ms
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Chapter 5 observation emphasis the
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Chapter 6 CHAPTER 6 NUMERICAL SIMUL
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Chapter 6 centered at the spark plu
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Chapter 6 H 2 O, (3) N 2 , (4) O 2
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Chapter 6 For all the above express
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Chapter 6 motions within the cylind
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Chapter 6 Heat transfer Wei et al.,
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Chapter 6 The calibration coefficie
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Chapter 6 6.3.2.2 In-cylinder volum
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Chapter 6 40 Experimental 30 Numeri
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Chapter 6 80 70 60 Numerical Experi
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Chapter 6 downdraft syngas than for
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Chapter 6 80 23º BTDC 60 29.5º BT
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Chapter 6 with experimental results
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Conclusions CHAPTER 7 CONCLUSIONS 7
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Conclusions radius and time for syn
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Conclusions conditions, therefore s
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Conclusions tel-00623090, version 1
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References References tel-00623090,
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References tel-00623090, version 1
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Appendix A - Overdetermined linear
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Appendix A - Overdetermined linear
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Appendix B- Syngas-air mixtures pro
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Appendix C -Rivère model Heat flux
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Appendix C -Rivère model The work
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tel-00623090, version 1 - 13 Sep 20
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